| Parameter |
Value |
| Designation |
28P/Neujmin 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-03-12T01:00:53.363520Z |
| Orbit solution date (soln_date, UTC) |
2026-06-05T08:28:30Z |
| Obs used |
1228 |
| NEO |
- |
| M1 |
13.200 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-09-01.0000000 |
| e |
0.77345394 |
| q (au) |
1.577999 |
| a (au) |
6.965466 |
| i (deg) |
14.311489 |
| Ω (om, deg) |
346.346287 |
| ω (w, deg) |
347.442917 |
| M (ma, deg) |
330.081078 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.735 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.735 |
| n |
2.000 |
| gf |
0.891 |
| gb |
-0.727 |
| k |
0.939 |
| δ90 |
1.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-09-20 00:00 |
09:45:30.95 |
+20:08:22.4 |
HIP 47946 |
23.20 |
| 2026-09-20 12:00 |
09:45:40.62 |
+20:07:39.2 |
HIP 47946 |
23.01 |
| 2026-09-21 00:00 |
09:45:50.25 |
+20:06:56.2 |
HIP 47946 |
23.05 |
| 2026-09-21 12:00 |
09:45:59.83 |
+20:06:13.6 |
HIP 47946 |
23.34 |
| 2026-09-22 00:00 |
09:46:09.37 |
+20:05:31.2 |
HIP 47946 |
23.85 |
| 2026-09-22 12:00 |
09:46:18.87 |
+20:04:49.2 |
HIP 47946 |
24.57 |
| 2026-09-23 00:00 |
09:46:28.33 |
+20:04:07.4 |
HIP 47946 |
25.47 |
| 2026-09-23 12:00 |
09:46:37.74 |
+20:03:26.0 |
HIP 47946 |
26.55 |
| 2026-09-24 00:00 |
09:46:47.10 |
+20:02:44.8 |
HIP 47946 |
27.76 |
| 2026-09-24 12:00 |
09:46:56.42 |
+20:02:04.0 |
HIP 47946 |
29.10 |
| 2026-09-25 00:00 |
09:47:05.69 |
+20:01:23.5 |
HIP 47946 |
30.55 |
| 2026-09-25 12:00 |
09:47:14.92 |
+20:00:43.3 |
HIP 47946 |
32.08 |
| 2026-09-26 00:00 |
09:47:24.10 |
+20:00:03.4 |
HIP 47946 |
33.68 |
| 2026-09-26 12:00 |
09:47:33.23 |
+19:59:23.9 |
HIP 48021 |
35.01 |
| 2026-09-27 00:00 |
09:47:42.32 |
+19:58:44.6 |
HIP 48021 |
34.60 |
| 2026-09-27 12:00 |
09:47:51.35 |
+19:58:05.7 |
HIP 48021 |
34.34 |
| 2026-09-28 00:00 |
09:48:00.34 |
+19:57:27.1 |
HIP 48021 |
34.23 |
| 2026-09-28 12:00 |
09:48:09.28 |
+19:56:48.9 |
HIP 48230 |
33.01 |
| 2026-09-29 00:00 |
09:48:18.17 |
+19:56:11.0 |
HIP 48230 |
30.99 |
| 2026-09-29 12:00 |
09:48:27.01 |
+19:55:33.4 |
HIP 48230 |
29.01 |
| 2026-09-30 00:00 |
09:48:35.79 |
+19:54:56.1 |
HIP 48230 |
27.06 |
| 2026-09-30 12:00 |
09:48:44.53 |
+19:54:19.2 |
HIP 48230 |
25.16 |
| 2026-10-01 00:00 |
09:48:53.22 |
+19:53:42.6 |
HIP 48230 |
23.32 |
| 2026-10-01 12:00 |
09:49:01.85 |
+19:53:06.4 |
HIP 48230 |
21.55 |
| 2026-10-02 00:00 |
09:49:10.43 |
+19:52:30.5 |
HIP 48230 |
19.85 |
| 2026-10-02 12:00 |
09:49:18.96 |
+19:51:55.0 |
HIP 48230 |
18.25 |
| 2026-10-03 00:00 |
09:49:27.43 |
+19:51:19.8 |
HIP 48230 |
16.77 |
| 2026-10-03 12:00 |
09:49:35.85 |
+19:50:45.0 |
HIP 48230 |
15.44 |
| 2026-10-04 00:00 |
09:49:44.22 |
+19:50:10.5 |
HIP 48230 |
14.29 |
| 2026-10-04 12:00 |
09:49:52.53 |
+19:49:36.4 |
HIP 48230 |
13.37 |
| 2026-10-05 00:00 |
09:50:00.78 |
+19:49:02.6 |
HIP 48230 |
12.71 |
| 2026-10-05 12:00 |
09:50:08.98 |
+19:48:29.3 |
HIP 48230 |
12.36 |
| 2026-10-06 00:00 |
09:50:17.12 |
+19:47:56.2 |
HIP 48230 |
12.33 |
| 2026-10-06 12:00 |
09:50:25.21 |
+19:47:23.6 |
HIP 48230 |
12.62 |
| 2026-10-07 00:00 |
09:50:33.23 |
+19:46:51.3 |
HIP 48230 |
13.20 |
| 2026-10-07 12:00 |
09:50:41.20 |
+19:46:19.4 |
HIP 48230 |
14.03 |
| 2026-10-08 00:00 |
09:50:49.11 |
+19:45:47.9 |
HIP 48230 |
15.06 |
| 2026-10-08 12:00 |
09:50:56.96 |
+19:45:16.8 |
HIP 48230 |
16.25 |
| 2026-10-09 00:00 |
09:51:04.75 |
+19:44:46.1 |
HIP 48230 |
17.56 |
| 2026-10-09 12:00 |
09:51:12.47 |
+19:44:15.7 |
HIP 48230 |
18.95 |
| 2026-10-10 00:00 |
09:51:20.14 |
+19:43:45.7 |
HIP 48230 |
20.42 |
| 2026-10-10 12:00 |
09:51:27.75 |
+19:43:16.2 |
HIP 48230 |
21.94 |
| 2026-10-11 00:00 |
09:51:35.29 |
+19:42:47.0 |
HIP 48230 |
23.49 |